In such a known step switch as described in German patent document 2,321,369 there are two selector arms each carrying a respective selector contact, the first of the movable selector contacts being connected to a vacuum switch intended for continuous-current transmission and interruption and the second of the movable selector contacts being connected to a vacuum switch and series-connected shunt resistor intended only for conducting and interrupting the compensating current. The two movable selector contacts are connected to each other and to the vacuum switch so that when the switching direction changes the rotation direction of the drive also changes and during each indexing of the second selector contact the vacuum switch that is intended only to conduct and interrupt the compensating current in series with the shunt resistor is left connected momentarily all alone to the tap at high voltage. With this known step switch according to the switching direction the resistance contact either leads or trails; the switching procedure is different depending on switching direction.
As a result both of the arms carrying the respective selector contacts must be jointly actuated by the energy-storage unit; this is particularly disadvantage due to the complex kinematics as well as the mechanically costly energy-storage unit which is required in particular by the different switching steps depending on switching direction.